1. Field
The present invention relates generally to wireless communication systems, and more specifically to a method for determining the home network carrier of a roaming mobile station that is attempting to access a local network.
2. Background
As the proliferation of wireless devices increases, mobile users often find themselves requesting services from service providers other than their home network providers, i.e. home network carriers. The industry has kept up with this situation by putting in place roaming agreements to provide mobile users with services while outside of their home areas. The local networks then each maintain information (e.g., in look-up tables) that can be used to identify which home networks are associated with roaming users, and which home networks are covered by the different roaming agreements.
When mobile users need service in areas outside the limits of their home networks, they contact a local network to request service. The request often includes a user name and password that is provided by the home network. This user name and password may, for example, be a publicly available user name that is common to many, if not all, users within the same home network carrier. Upon receiving the request from the mobile user, the local network uses its locally stored information to determine which of the home networks is associated with the user and whether, based on that association, the user should be granted the requested services. This may include checking the user name and password in the user's request for service against the authorization information stored with the home network's information.
This arrangement necessities not only the initial expense of setting up the local storage of the information for all of the home networks, but also the recurring expense of maintaining the information in each of the local networks. For instance, when the information associated with carrier A changes (e.g., the status of roaming agreements, user names, passwords, etc.,) this information must be updated in each of the local networks, in case a user associated with network A roams in an area associated with one of the local networks. Delays or errors in the process of updating the network information can cause denials of service to mobile users that otherwise should have been granted access to the local network. This results in frustrated mobile users and lost revenue for both the local network carrier and the home network carrier.
It is clear that the difficulties of maintaining the same home network information in each of the local networks are made worse by scaling. If there are more home networks, there is more information that has to be maintained at each local network. If there are more local networks, the difficulties of keeping the information in all of the local networks are exacerbated. (It may be noted that a given network may be considered a local network or a home network, depending upon the association of the respective networks with particular mobile users.)
There is therefore a need in the art for systems and methods for authorizing access by roaming mobile users to a local network that does not suffer from the drawbacks of conventional systems and methods.